As global temperature rise,the threat of heat stress to rapeseed production is becoming more obvious.Exploring the response characteristics of two important biological pathways,oil accumulation and photosynthesis,to h...As global temperature rise,the threat of heat stress to rapeseed production is becoming more obvious.Exploring the response characteristics of two important biological pathways,oil accumulation and photosynthesis,to heat stress during B.napus seed filling is helpful in the genetic improvement of heat-tolerant rapeseed.The effects of heat stress on seed oil accumulation and chlorophyll fluorescence characteristics of 29 B.napus germplasms with different oil content and environmental sensitivity,including 6 rapeseed varieties which exhibited environmentsensitive/insensitive and with high,medium or low oil content,were tested by whole plant heat stress or the in vitro silique culture system.Both assay exhibited similar trend on oil content of the rapeseed germplasms.The heat effect on the chlorophyll fluorescence kinetic parameters F_(v)/F_(m),ETR and Y(Ⅱ)were also consistent.Heat stress significantly decreased oil content,although there was abundant genetic variation on heat tolerance among the genotypes.Correlation analysis showed that the decrease rate of F_(v)/F_(m) of silique heat-stressed B.napus developing seed was positive correlative to the decrease rate of mature seed oil content of the whole plant heat-stressed rapeseed(R=0.9214,P-value<0.01).Overall,the results indicated that heat stress inhibited oil accumulation and photosynthesis in B.napus developing seed.The decrease rate of chlorophyll fluorescence parameter F_(v)/F_(m) of heat-stressed developing seed could be used as the index of heat tolerant rapeseed identification.Further,two heat insensitive rapeseed varieties with high oil content were identified.展开更多
The accumulation of undesirable deposits on the heat exchange surface represents a critical issue in industrial heat exchangers.Taking experimental measurements of the fouling is relatively difficult and,often,this me...The accumulation of undesirable deposits on the heat exchange surface represents a critical issue in industrial heat exchangers.Taking experimental measurements of the fouling is relatively difficult and,often,this method does not lead to precise results.To overcome these problems,in the present study,a new approach based on an Artificial Neural Network(ANN)is used to predict the fouling resistance as a function of specific measurable variables in the phosphoric acid concentration process.These include:the phosphoric acid inlet and outlet temperatures,the steam temperature,the phosphoric acid density,the phosphoric acid volume flow rate circulating in the loop.Some statistical accuracy indices are employed simultaneously to justify the interrelation between these independent variables and the fouling resistance and to select the best training algorithm allowing the determination of the optimal number of hidden neurons.In particular,the BFGS quasi-Newton back-propagation approach is found to be the most performing of the considered training algorithms.Furthermore,the best topology ANN for the shell and tube heat exchanger is obtained with a network consisting of one hidden layer with 13 neurons using a tangent sigmoid transfer function for the hidden and output layers.This model predicts the experimental values of the fouling resistance with AARD%=0.065,MSE=2.168×10^(−11),RMSE=4.656×10^(−6)and r^(2)=0.994.展开更多
Generally MPPT control (maximum power point tracking) is adopted to control of a thermoelectric generator. However, in the case of generation by use of a heat accumulator MPPT control cannot obtain maximum whole elect...Generally MPPT control (maximum power point tracking) is adopted to control of a thermoelectric generator. However, in the case of generation by use of a heat accumulator MPPT control cannot obtain maximum whole electrical output during the operation period. This is because the amount of heat stored in a heat accumulator is limited and easy to be exhausted rapidly by MPPT. Therefore MEPT (Maximum Efficiency Point Tracking) control should be developed to obtain maximum power from limited heat stored in the heat accumulator. When thermoelectric generator is used for waste heat recovery, conversion efficiency is quite difficult to be measured. This is due to time delay between the change of temperature profile in the thermoelectric generator and the change of heat medium temperature. Decrease of output current is desired to enlarge output because decrease of current decreases Peltier heat and improves efficiency of heat recovery. The experimental results indicate that current fluctuated by MPPT control causes loss of power output. We proposed the optimal control in which current is 10% smaller than one of MPPT control and evaluated it experimentally. We call this control scheme MEPT control. In this evaluation 500 W class thermoelectric generator, latent heat accumulator and the test facilities included 30 kW electric heater are utilized. Experimental result shows MEPT control exceeds MPPT in total electricity recovered from heat accumulator.展开更多
The technique of modeling operating temperature variations of shell-and-tube heat exchanger 10-E-01 of kerosene-crude oil streams of Port Harcourt refinery crude distillation unit is presented in this research. A...The technique of modeling operating temperature variations of shell-and-tube heat exchanger 10-E-01 of kerosene-crude oil streams of Port Harcourt refinery crude distillation unit is presented in this research. Appropriate first-order model equations were developed applying principles of energy balance. The differential equations developed for the process streams which exchanged heat was evaluated numerically to predict the temperature variations as a function of time. The relevant parameters associated with typical heat exchanger works were calculated using plant data of 10-E-02. The model strives to predict the final kerosene temperature from 488 to 353.6 K. While the crude oil streams temperature rose from 313 to 353.6 K. The developed model enables the operator to predict the final temperature at the kerosene hydro-treating unit and thereby prevent regular emergency shutdowns due to excessive temperature rise.展开更多
目的探讨清热利湿方治疗糖尿病肠病疗效及对患者生活质量的影响。方法将48例湿热内蕴证糖尿病肠病患者按随机数字表法分观察组和对照组,每组24例;两组均口服美沙拉嗪肠溶片,观察组加予清热利湿方日2次口服治疗,统计肠炎疾病量表(inflamm...目的探讨清热利湿方治疗糖尿病肠病疗效及对患者生活质量的影响。方法将48例湿热内蕴证糖尿病肠病患者按随机数字表法分观察组和对照组,每组24例;两组均口服美沙拉嗪肠溶片,观察组加予清热利湿方日2次口服治疗,统计肠炎疾病量表(inflammatory bowel disease questionnaire,IBDQ)评分及相关症状体征。结果观察组与对照组IBDQ评分各分项得分治疗后均高于治疗前,但观察组分数增加较为明显,且观察组在全身症状、肠道症状、情感功能、社会功能、总分等方面得分增加均高于对照组,在全身症状改善方面尤为显著。两组在生活质量量表(the MOS item short from health survey,SF-36)量表中生理机能(physical functioning,PF)、生理职能(role physical,RP)、活力(vitality,VT)、精神健康(mental health,MH)、整体健康(general health,GH)等方面治疗前与治疗后差异有统计学意义(均P<0.05)。观察组总有效率91.67%(22/24),两组间疗效比较差异有统计学意义(P<0.05)。两组病例均耐受良好,未见明显不良反应,1年内复发率观察组低于对照组(均P<0.05)。结论清热利湿方可以有效清热利湿,改善患者病情,是针对糖尿病肠病的一种有效治疗方案,可以提高湿热内蕴证糖尿病肠病患者的治疗有效率,明显提高患者的生活质量,值得临床进一步研究及推广。展开更多
基金funded by the Natural Science Foundation of Zhejiang Province(LY20C130006)the National Natural Science Foundation of China(32172018)the State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products(2010DS700124-ZZ1805).
文摘As global temperature rise,the threat of heat stress to rapeseed production is becoming more obvious.Exploring the response characteristics of two important biological pathways,oil accumulation and photosynthesis,to heat stress during B.napus seed filling is helpful in the genetic improvement of heat-tolerant rapeseed.The effects of heat stress on seed oil accumulation and chlorophyll fluorescence characteristics of 29 B.napus germplasms with different oil content and environmental sensitivity,including 6 rapeseed varieties which exhibited environmentsensitive/insensitive and with high,medium or low oil content,were tested by whole plant heat stress or the in vitro silique culture system.Both assay exhibited similar trend on oil content of the rapeseed germplasms.The heat effect on the chlorophyll fluorescence kinetic parameters F_(v)/F_(m),ETR and Y(Ⅱ)were also consistent.Heat stress significantly decreased oil content,although there was abundant genetic variation on heat tolerance among the genotypes.Correlation analysis showed that the decrease rate of F_(v)/F_(m) of silique heat-stressed B.napus developing seed was positive correlative to the decrease rate of mature seed oil content of the whole plant heat-stressed rapeseed(R=0.9214,P-value<0.01).Overall,the results indicated that heat stress inhibited oil accumulation and photosynthesis in B.napus developing seed.The decrease rate of chlorophyll fluorescence parameter F_(v)/F_(m) of heat-stressed developing seed could be used as the index of heat tolerant rapeseed identification.Further,two heat insensitive rapeseed varieties with high oil content were identified.
文摘The accumulation of undesirable deposits on the heat exchange surface represents a critical issue in industrial heat exchangers.Taking experimental measurements of the fouling is relatively difficult and,often,this method does not lead to precise results.To overcome these problems,in the present study,a new approach based on an Artificial Neural Network(ANN)is used to predict the fouling resistance as a function of specific measurable variables in the phosphoric acid concentration process.These include:the phosphoric acid inlet and outlet temperatures,the steam temperature,the phosphoric acid density,the phosphoric acid volume flow rate circulating in the loop.Some statistical accuracy indices are employed simultaneously to justify the interrelation between these independent variables and the fouling resistance and to select the best training algorithm allowing the determination of the optimal number of hidden neurons.In particular,the BFGS quasi-Newton back-propagation approach is found to be the most performing of the considered training algorithms.Furthermore,the best topology ANN for the shell and tube heat exchanger is obtained with a network consisting of one hidden layer with 13 neurons using a tangent sigmoid transfer function for the hidden and output layers.This model predicts the experimental values of the fouling resistance with AARD%=0.065,MSE=2.168×10^(−11),RMSE=4.656×10^(−6)and r^(2)=0.994.
文摘Generally MPPT control (maximum power point tracking) is adopted to control of a thermoelectric generator. However, in the case of generation by use of a heat accumulator MPPT control cannot obtain maximum whole electrical output during the operation period. This is because the amount of heat stored in a heat accumulator is limited and easy to be exhausted rapidly by MPPT. Therefore MEPT (Maximum Efficiency Point Tracking) control should be developed to obtain maximum power from limited heat stored in the heat accumulator. When thermoelectric generator is used for waste heat recovery, conversion efficiency is quite difficult to be measured. This is due to time delay between the change of temperature profile in the thermoelectric generator and the change of heat medium temperature. Decrease of output current is desired to enlarge output because decrease of current decreases Peltier heat and improves efficiency of heat recovery. The experimental results indicate that current fluctuated by MPPT control causes loss of power output. We proposed the optimal control in which current is 10% smaller than one of MPPT control and evaluated it experimentally. We call this control scheme MEPT control. In this evaluation 500 W class thermoelectric generator, latent heat accumulator and the test facilities included 30 kW electric heater are utilized. Experimental result shows MEPT control exceeds MPPT in total electricity recovered from heat accumulator.
文摘The technique of modeling operating temperature variations of shell-and-tube heat exchanger 10-E-01 of kerosene-crude oil streams of Port Harcourt refinery crude distillation unit is presented in this research. Appropriate first-order model equations were developed applying principles of energy balance. The differential equations developed for the process streams which exchanged heat was evaluated numerically to predict the temperature variations as a function of time. The relevant parameters associated with typical heat exchanger works were calculated using plant data of 10-E-02. The model strives to predict the final kerosene temperature from 488 to 353.6 K. While the crude oil streams temperature rose from 313 to 353.6 K. The developed model enables the operator to predict the final temperature at the kerosene hydro-treating unit and thereby prevent regular emergency shutdowns due to excessive temperature rise.
文摘目的探讨清热利湿方治疗糖尿病肠病疗效及对患者生活质量的影响。方法将48例湿热内蕴证糖尿病肠病患者按随机数字表法分观察组和对照组,每组24例;两组均口服美沙拉嗪肠溶片,观察组加予清热利湿方日2次口服治疗,统计肠炎疾病量表(inflammatory bowel disease questionnaire,IBDQ)评分及相关症状体征。结果观察组与对照组IBDQ评分各分项得分治疗后均高于治疗前,但观察组分数增加较为明显,且观察组在全身症状、肠道症状、情感功能、社会功能、总分等方面得分增加均高于对照组,在全身症状改善方面尤为显著。两组在生活质量量表(the MOS item short from health survey,SF-36)量表中生理机能(physical functioning,PF)、生理职能(role physical,RP)、活力(vitality,VT)、精神健康(mental health,MH)、整体健康(general health,GH)等方面治疗前与治疗后差异有统计学意义(均P<0.05)。观察组总有效率91.67%(22/24),两组间疗效比较差异有统计学意义(P<0.05)。两组病例均耐受良好,未见明显不良反应,1年内复发率观察组低于对照组(均P<0.05)。结论清热利湿方可以有效清热利湿,改善患者病情,是针对糖尿病肠病的一种有效治疗方案,可以提高湿热内蕴证糖尿病肠病患者的治疗有效率,明显提高患者的生活质量,值得临床进一步研究及推广。
